this.SetStyle(ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;

namespace SkypeLookControls
{
    public partial class SkypeProgressBar : UserControl
    {
        private int _min = 0;
        private int _max = 100;
        private int _value = 0;

        private Point[] _borderPoints = null;

        private Color borderColor = Color.FromArgb(174, 179, 179);
        private Color brightDisabledColor = Color.FromArgb(222, 222, 222);

        private Color darkDisabledColor1 = Color.FromArgb(209, 209, 209);
        private Color darkDisabledColor2 = Color.FromArgb(216, 216, 216);

        private Color brightActiveColor = Color.FromArgb(0, 183, 254);
        private Color darkActiveColor1 = Color.FromArgb(0, 167, 233);
        private Color darkActiveColor2 = Color.FromArgb(0, 183, 254);

        /// <summary>
        /// Gets or sets the minimum.
        /// </summary>
        /// <value>The minimum.</value>
        public int Minimum
        {
            get { return this._min; }
            set { this._min = value; }
        }

        /// <summary>
        /// Gets or sets the maximum.
        /// </summary>
        /// <value>The maximum.</value>
        public int Maximum
        {
            get { return this._max; }
            set { this._max = value; }
        }

        /// <summary>
        /// Gets or sets the value.
        /// </summary>
        /// <value>The value.</value>
        public int Value
        {
            get { return this._value; }
            set { this._value = value; this.Invalidate(); this.Update(); }
        }

        /// <summary>
        /// Initializes a new instance of the 
        /// <see cref="SkypeProgressBar"/> class.
        /// </summary>
        public SkypeProgressBar()
        {
            InitializeComponent();

            this.SetStyle(ControlStyles.UserPaint, true);
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);

            Init();

            this.Resize += new EventHandler(SkypeProgressBar_Resize);
        }

        void SkypeProgressBar_Resize(object sender, EventArgs e)
        {
            Init();

            this.Invalidate();
            this.Update();
        }

        private void Init()
        {
            this._borderPoints = new Point[9];
            Point p1 = new Point(3, 1);
            Point p2 = new Point(this.Width - 3, 1);
            Point p3 = new Point(this.Width - 1, 3);
            Point p4 = new Point(this.Width - 1, this.Height - 3);
            Point p5 = new Point(this.Width - 3, this.Height - 1);
            Point p6 = new Point(3, this.Height - 1);
            Point p7 = new Point(1, this.Height - 3);
            Point p8 = new Point(1, 3);
            Point p9 = new Point(3, 1);

            this._borderPoints[0] = p1;
            this._borderPoints[1] = p2;
            this._borderPoints[2] = p3;
            this._borderPoints[3] = p4;
            this._borderPoints[4] = p5;
            this._borderPoints[5] = p6;
            this._borderPoints[6] = p7;
            this._borderPoints[7] = p8;
            this._borderPoints[8] = p9;
        }

        /// <summary>
        /// Raises the 
        /// <see cref="E:System.Windows.Forms.Control.Paint"></see> 
        /// event.
        /// </summary>
        /// <param name="e">A 
        /// <see cref="T:System.Windows.Forms.PaintEventArgs"></see> 
        /// that contains the event data.</param>
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            Point[] points = new Point[4];
            Point p1 = new Point(0,0);
            Point p2 = new Point(this.Width, 0);
            Point p3 = new Point(this.Width, this.Height);
            Point p4 = new Point(0, this.Height);
            points[0] = p1;
            points[1] = p2;
            points[2] = p3;
            points[3] = p4;

            e.Graphics.DrawPolygon(
                new Pen(new SolidBrush(this.BackColor)), points);

            PaintBorder(e);
            PaintBar(e);
        }

        /// <summary>
        /// Paints the border.
        /// </summary>
        /// <param name="e">The 
        /// <see cref="System.Windows.Forms.PaintEventArgs"/> 
        /// instance containing the event data.</param>
        private void PaintBorder(PaintEventArgs e)
        {
            Pen p = new Pen(new SolidBrush(this.borderColor));
            e.Graphics.DrawLines(p, this._borderPoints);
        }

        /// <summary>
        /// Paints the disabled part of the progress bar.
        /// </summary>
        /// <param name="e">The 
        /// <see cref="System.Windows.Forms.PaintEventArgs"/> 
        /// instance containing the event data.</param>
        private void PaintDisabledPart(PaintEventArgs e)
        {
            int y = (this.Height-6) / 2;

            LinearGradientBrush lgb = 
                new LinearGradientBrush(
                    new Rectangle(3,y, this.Width-5, this.Height-y-3), 
                    this.darkDisabledColor1, 
                    this.darkDisabledColor2, 
                    90f);
            e.Graphics.FillRectangle(lgb, 
                    new Rectangle(3, y+1, this.Width - 5, this.Height-y-3));

            e.Graphics.FillRectangle(
                    new SolidBrush(this.brightDisabledColor), 
                    new Rectangle(3, 3, this.Width - 5, y));
        }

        /// <summary>
        /// Paints the active part of the progress bar.
        /// </summary>
        /// <param name="e">The 
        /// <see cref="System.Windows.Forms.PaintEventArgs"/> 
        /// instance containing the event data.</param>
        private void PaintActivePart(PaintEventArgs e)
        {
            int y = (this.Height - 6) / 2;
            double width = (this.Width - 6d) / 
                (double) this.Maximum * (double)this.Value;

            if (Value == Maximum)
                width = this.Width - 6d;

            if (width > 0)
            {
                LinearGradientBrush lgb = 
                    new LinearGradientBrush(
                        new Rectangle(3, y, (int)width, this.Height - y - 3), 
                        this.darkActiveColor1, 
                        this.darkActiveColor2, 
                        90f);
                e.Graphics.FillRectangle(lgb, 
                    new Rectangle(3, y + 1, (int)width, this.Height - y - 3));

                e.Graphics.FillRectangle(
                    new SolidBrush(this.brightActiveColor), 
                    new Rectangle(3, 3, (int)width, y));
            }
        }

        /// <summary>
        /// Paints the progress bar.
        /// </summary>
        /// <param name="e">The 
        /// <see cref="System.Windows.Forms.PaintEventArgs"/> 
        /// instance containing the event data.</param>
        private void PaintBar(PaintEventArgs e)
        {
            PaintDisabledPart(e);
            PaintActivePart(e);
        }
    }
}

this.Background = Color.Transparent;

protected override CreateParams CreateParams
{
    get
    {
        CreateParams cp = base.CreateParams;
        cp.ExStyle := 0x20;
        return cp;
    }
}

protected override void OnPaintBackground
    (PaintEventArgs pevent)
{
    // do nothing in this case
}

protected override void OnMove(EventArgs e)
{
    RecreateHandle();
}